Laser beam combining has been used for increasing power, for double pulse processing, and for creating beams having more than one wavelength.
U.S. Pat. No. 5,742,626 describes splitting a beam, passing one portion of it through a harmonic converter and remixing the beam portions in a sum frequency generator to obtain a deep UV beam.
U.S. Pat. No. 5,756,924 employs a beam combiner for providing coaxial propagation of combined laser outputs and subsequent spatial overlap in the focal volume of a focusing lens.
U.S. Pat. No. 6,266,359 proposes a splicing asymmetric reflective array for combining two beams.
U.S. Pat. Appl. Pub. No. 2003-0151053 proposes a method of combining laser pulses from two lasers using synchronizing electronics and a triggering delay.
U.S. Pat. No. 6,541,731 proposes beam combining to provide multiple working beams, or a combined beam, of different polarizations. In one embodiment, an electro-optic modulator appears to be employed as a pulse picker.
U.S. Pat. Appl. Pub. No. 2004-0134894 also appears to propose a method of combining laser pulses (or generating a sequence of closely spaced pulses) from two lasers using delayed triggering. The described configuration of seed pulses working with an optical amplifier is of a standard design because the combiner has low efficiency.
U.S. Pat. No. 7,396,706 describes combining synchronized pulses from two Q-switched lasers to provide laser output having the same or different energy and/or wavelength features from both pulses.
U.S. Pat. Appl. Pub. No. 2006-0198402 combines pulses from four extra-cavity, frequency-tripled lasers to provide a combined pulse of predetermined energy.
U.S. Pat. No. 7,199,924 proposes combining two beams using a wavelength-dispersion compensation combiner having a plurality of asymmetric gratings.
These patents and publications offer some advantages for implementing their specific applications but suffer from disadvantages when applied to other applications.